export default {
  //为当前模块开启命名空间
  namespaced: true,

  //模块的state数据
  state: () => ({
    //购物车的数组，用来存储购物车中每个商品的信息对象
    // 每个商品的信息对象,都包含如下6个属性:
    // {goods_id,goods_name,goods_price,goods_count,goods_small_logo,goods_state}
    cart: JSON.parse(uni.getStorageSync('cart') || '[]'),
  }),
  //模块的mutations方法
  mutations: {
    addToCart(state, goods) {
      //根据提交的商品的id，查询购物车中是否存在该商品
      //若不存在，则findResult为undefined,否则，为查找到的商品信息对象
      const findReult = state.cart.find(x => x.goods_id === goods.goods_id)
      if (!findReult) {
        state.cart.push(goods)
      } else {
        findReult.goods_count++
      }

      //通过commint方法，调用m_cart命名空间下的saveToStorage方法
      this.commit('m_cart/saveToStorage')
    },
    saveToStorage(state) {
      uni.setStorageSync('cart', JSON.stringify(state.cart))
    },
    //修改购物车中商品的勾选状态
    updateGoodsState(state, goods) {
      const findReult = state.cart.find(x => x.goods_id === goods.goods_id)
      if (findReult) {
        findReult.goods_state = goods.goods_state
      }
      //持久化存储到本地
      this.commit('m_cart/saveToStorage')
    },
    updateGoodsCount(state, goods) {
      const findReult = state.cart.find(x => x.goods_id === goods.goods_id)
      if (findReult) {
        findReult.goods_count = goods.goods_count
      }
      //持久化存储到本地
      this.commit('m_cart/saveToStorage')
    },
    removeGoodsById(state, goods_id) {
      state.cart = state.cart.filter(x => x.goods_id !== goods_id)
      this.commit('m_cart/saveToStorage')
    },
    updateAllGoodsState(state, newState) {
      state.cart.forEach(x => x.goods_state = newState)
      this.commit('m_cart/saveToStorage')
    },

  },

  //模块的getters属性
  getters: {


    //统计购物车中所有商品的总数量
    total(state) {
      // let c = 0
      // state.cart.forEach(goods => c += goods.goods_count)
      // return c
      return state.cart.reduce((total, item) => total += item.goods_count, 0)
    },
    //购物车中已勾选商品的总数量
    checkedCount(state) {
      //reduce，遍历所有项，并将累计值赋给total
      return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count, 0)
    },
    checkedGoodsAmount(state) {
      //reduce，遍历所有项，并将累计值赋给total
      return state.cart.filter(x => x.goods_state)
        .reduce((total, item) => total += item.goods_count * item.goods_price, 0)
        .toFixed(2)
    },
  },

}